CADMIUM INDUCES APOPTOSIS DIFFERENTIALLY ON IMMUNE-SYSTEM CELL-LINES

We investigate the role of cadmium-induced apoptosis in the immune sys tem, studying the apoptotic effect of Cd2+ in three human cell lines, the T-cell line CCRF-CEM, the B-cell line Raji and the lymphoblastoid cell line Molt-3. Cd2+ was found to be dose-dependently toxic for thes e cell lines, after 18 h incubation. The 50% lethal dose (LD50) for CC RF-CEM was 25+/-20 mu M, for Molt-3 was 22.5+/-2.4 mu M, and for Raji was 13.5+/-2.2 mu M. DNA electrophoresis and quantitation of apoptosis after 18 h incubation with different Cd2+ concentrations was carried out. In CCRF-CEM cells, apoptosis was detected at 10 mu M, reaching a maximum at 30 mu M. In Molt-3, apoptosis was detected at 10 mu M, incr eased thereafter and a plateau effect was observed from 30 to 50 mu M Cd2+. In Raji, apoptosis was detected at 5 mu M, while a plateau effec t was observed from 20 to 30 mu M Cd2+. The above results indicated th at Raji cells were more sensitive to cadmium compared to both CCRF-CEM and Molt-3 cells, suggesting a differential Cd2+-induced apoptotic ef fect, which may disturb the immune system normal growth and developmen t. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.